(1) Field of the Invention
The present invention is related to a sewing machine and characterized by forming a machine with a vertical cut-off part of the bed of a sewing machine at an appropriate point on the right-hand side of a rise-and-fall position of a needle, and also forming a sewing unit provided with a needle plate, a feeding teeth, a shuttle or a looper, etc., and connecting the sewing unit to the cut-off part of the bed of the sewing machine so as to perform a desired stitching.
(2) State of the Prior Art
Conventional sewing machines may be divided into two types, for example, a locking stitching machine which can perform lock stitching or zigzag stitching optionally, and a lock stitching machine which can perform over-lock stitching or cover hemming.
Further, there is a sewing machine as disclosed in U.S. Pat. No. 4,967,677, owned by the applicant of the present application, and applicable to a combined use for lock stitching and over-lock stitching.
The above-mentioned conventional sewing machine having a combined use for lock stitching and over-lock stitching is provided on a portion of a bed with a shuttle and a driving means for lock stitching, and at the same time is provided with upper and lower loopers and driving means for over-lock stitching. It is able to select either lock stitching or over-lock stitching by operating an actuation switch-over means provided on the bed portion.
Among the above-mentioned conventional sewing machines, the first cited machines are respectively of almost single capacity. Therefore, in the case of users desiring various kinds of stitchings, it is required to have a plural number of sewing machines of different stitching functions. Thus, users need to buy many sewing machines.
While in the case of the example cited last, over-lock stitching as well as lock stitching including zigzag stitching and pattern stitching can be performed by a single sewing machine. Therefore, the latter has an advantage in that it is less expensive than the former, but, at the same time it has a disadvantage in that it has to set various elements in its narrow bed, and thereby becomes complicated in structure, difficult to assemble and high in manufacturing cost, Moreover, the functions given to the machine may interfere with each other and thereby cannot be fully used.
Thus, it has been a problem to develop a sewing machine which is easy for users to operate and easy to manufacture while being hard to break down, and which enables users to perform their desired mode of stitching selectively.